Blue Sea Systems 4-Position Battery Switch

[Triton318]

Listed on eBay; Item number: 130190124225

I purchased this Blue Sea Systems battery switch, product number 9002, in 2002. It is a 4-position switch: Off, 1, 2, Both. It is rated for 6-32 volts, 300 amps continuous, 400 amps intermittent. In addition to the three large terminals on the back, there are two small terminals labeled F1 and F2. I'm not sure what these are for; I never used them. I believe it may be the optional AFD (alternator field disconnect).

Works perfectly and looks good too.

The reason I'm selling this switch is that I'm doing some work to my boat, which includes simplifying the electrical system.

[David M]

You are correct. It has to do with protecting your alternator. You cut your alternator field wire and place it across F1 and F2. It prevents accidental alternator damage should someone turn off the battery switch while the alternator is running.

The downside with running your alternator field wire all the way to your battery switch and back, is if the field wire breaks, your alternator goes dead.

As you have already started doing, it is probably best to keep things simple.

http://www.jackrabbitmarine.com/file..._Datasheet.pdf

You can also purchase a "Zap Stopper", a diode for your alternator, that serves the same purpose....with no negative consequences if this wire breaks, other than it no longer does its job.

[GordMay]

Alternator Field Disconnect
Alternator Field Disconnect - Resources - Blue Sea Systems

Note: If the distance fronm the Battery to the Selector Switch is more than 72", Overcurrent Protection (Fuse/Breaker) is required (not shown in diagram).
I recommend a fuse/breaker in every conductor, excepting Starter Cranking conductors.